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Chida A, Shintani M, Yagi H, Fujiwara M, Kojima Y, Sato H, Imamura S, Yokozawa M, Onodera N, Horigome H, Kobayashi T, Hatai Y, Nakayama T, Fukushima H, Nishiyama M, Doi S, Ono Y, Yasukouchi S, Ichida F, Fujimoto K, Ohtsuki S, Teshima H, Kawano T, Nomura Y, Gu H, Ishiwata T, Furutani Y, Inai K, Saji T, Matsuoka R, Nonoyama S, Nakanishi T. Outcomes of childhood pulmonary arterial hypertension in BMPR2 and ALK1 mutation carriers. Am J Cardiol 2012; 110:586-93. [PMID: 22632830 DOI: 10.1016/j.amjcard.2012.04.035] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2012] [Revised: 04/03/2012] [Accepted: 04/03/2012] [Indexed: 01/23/2023]
Abstract
Mutations in the bone morphogenetic protein receptor type 2 (BMPR2) gene and the activin receptor-like kinase 1 (ALK1) gene have been reported in heritable pulmonary arterial hypertension (HPAH) and idiopathic pulmonary arterial hypertension (IPAH). However, the relation between clinical characteristics and each gene mutation in IPAH and HPAH is still unclear, especially in childhood. The aim of this study was to determine, in a retrospective study, the influence and clinical outcomes of gene mutations in childhood IPAH and HPAH. Fifty-four patients with IPAH or HPAH whose onset of disease was at <16 years of age were included. Functional characteristics, hemodynamic parameters, and clinical outcomes were compared in BMPR2 and ALK1 mutation carriers and noncarriers. Overall 5-year survival for all patients was 76%. Eighteen BMPR2 mutation carriers and 7 ALK1 mutation carriers were detected in the 54 patients with childhood IPAH or HPAH. Five-year survival was lower in BMPR2 mutation carriers than mutation noncarriers (55% vs 90%, hazard ratio 12.54, p = 0.0003). ALK1 mutation carriers also had a tendency to have worse outcome than mutation noncarriers (5-year survival rate 64%, hazard ratio 5.14, p = 0.1205). In conclusion, patients with childhood IPAH or HPAH with BMPR2 mutation have the poorest clinical outcomes. ALK1 mutation carriers tended to have worse outcomes than mutation noncarriers. It is important to consider aggressive treatment for BMPR2 or ALK1 mutation carriers.
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Affiliation(s)
- Ayako Chida
- Department of Pediatrics, National Defense Medical College, Tokorozawa, Japan
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2
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Novel promoter and exon mutations of the BMPR2 gene in Chinese patients with pulmonary arterial hypertension. Eur J Hum Genet 2009; 17:1063-9. [PMID: 19223935 DOI: 10.1038/ejhg.2009.3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Pulmonary arterial hypertension (PAH), which is clinically characterized by a sustained elevation in mean pulmonary artery pressure leading to significant morbidity and mortality, is caused by intense remodeling of small pulmonary arteries by endothelial and smooth muscle proliferation. Genetic studies in familial PAH (FPAH) have revealed heterozygous germline mutations in the bone morphogenetic protein type II receptor (BMPR2), a receptor for the transforming growth factor (TGF)-beta/BMP superfamily. In this study, we conducted mutation screening in the promoter region and the entire coding regions as well as the intron/exon boundaries of the BMPR2 gene in 20 Chinese patients with either idiopathic or FPAH. All novel detected mutations were excluded by their presence in a panel of 200 chromosomes from normal individuals. A novel mutation, G-669A, in the promoter sequence of the BMPR2 gene was identified in one patient with FPAH, and no exonic mutations were detected in the proband. This mutation abolished a potential specificity protein 3 (sp3) transcription factor-binding site, and a dual luciferase assay showed that the promoter carrying the -669A allele had significantly decreased transcriptional activity compared with -669G allele. Of the other 19 patients, three novel heterozygous exonic mutations were identified: a frame shift mutation with deletion of TG at the nucleotide position 608-609 in exon 5 (Leu203fsX15), a nonsense mutation at the nucleotide position 292 in exon 3 (Glu98X) and a missense single nucleotide substitution in exon 12 (Ser863Asn).
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Fujiwara M, Yagi H, Matsuoka R, Akimoto K, Furutani M, Imamura SI, Uehara R, Nakayama T, Takao A, Nakazawa M, Saji T. Implications of mutations of activin receptor-like kinase 1 gene (ALK1) in addition to bone morphogenetic protein receptor II gene (BMPR2) in children with pulmonary arterial hypertension. Circ J 2008; 72:127-33. [PMID: 18159113 DOI: 10.1253/circj.72.127] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Mutations of the bone morphogenetic protein receptor II gene (BMPR2), and 1 mutation of the activin receptor-like kinase 1 gene (ALK1) have been reported in patients with pulmonary arterial hypertension (PAH). METHODS AND RESULTS A genomic study of ALK1 and BMPR2 was conducted in 21 PAH probands under 16 years of age to study the relationship between the clinical features of the patients and these genes. In all 4 familial aggregates of PAH, 3 ALK1 or 1 BMPR2 mutations were identified. Among 17 probands aged between 4 and 14 years with idiopathic PAH, 2 ALK1 mutations (2/17: 11.8%) and 3 BMPR2 mutations (3/17: 17.6%; 5 mutations in total: 5/17: 29.4%) were found. CONCLUSION Each proband with the ALK1 mutation developed PAH, as did the probands with the BMPR2 mutation. Hence, it is proposed that ALK1 plays as notable a role as BMPR2 in the etiology of PAH. Furthermore, asymptomatic carriers with the ALK1 mutation within the serine - threonine kinase domain are at risk of developing PAH and hereditary hemorrhagic telangiectasia, so close follow-up is recommended for those individuals.
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Affiliation(s)
- Maya Fujiwara
- Division of Pediatric Cardiology, Institute of Advanced Biomedical Engineering and Science, Graduate School of Medicine, Tokyo Women's Medical University, Tokyo, Japan
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Machado RD, Aldred MA, James V, Harrison RE, Patel B, Schwalbe EC, Gruenig E, Janssen B, Koehler R, Seeger W, Eickelberg O, Olschewski H, Elliott CG, Glissmeyer E, Carlquist J, Kim M, Torbicki A, Fijalkowska A, Szewczyk G, Parma J, Abramowicz MJ, Galie N, Morisaki H, Kyotani S, Nakanishi N, Morisaki T, Humbert M, Simonneau G, Sitbon O, Soubrier F, Coulet F, Morrell NW, Trembath RC. Mutations of the TGF-beta type II receptor BMPR2 in pulmonary arterial hypertension. Hum Mutat 2006; 27:121-32. [PMID: 16429395 DOI: 10.1002/humu.20285] [Citation(s) in RCA: 275] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Pulmonary arterial hypertension (PAH) is clinically characterized by a sustained elevation in mean pulmonary artery pressure leading to significant morbidity and mortality. The disorder is typically sporadic, and in such cases the term idiopathic PAH (IPAH) is used. However, cases that occur within families (familial PAH (FPAH)) display similar clinical and histopathological features, suggesting a common etiology. Heterozygous mutations of a type II member of the TGF-beta cell signaling superfamily known as BMPR2 on chromosome 2q33 have been identified in many kindreds with FPAH, yet display both reduced penetrance and sex bias. This report presents the compilation of data for 144 distinct mutations that alter the coding sequence of the BMPR2 gene identified in 210 independent PAH subjects. This large data set characterizes the extent of sequence variation and reveals that the majority (71%) of mutations in FPAH and IPAH comprise nonsense, frameshift, and splice-site defects, and gene rearrangements. These predict premature termination of the transcript with likely loss through the process of nonsense-mediated decay (NMD). A total of 44 missense mutations were identified that substitute amino acid residues at highly conserved sites within recognized functional domains of the mature receptor. We assess this category of mutations in the context of their heterogeneous effects on cell signaling when assayed by in vitro cell-based systems. Disease-causing mutation hot-spots within BMPR2 are summarized. Taken together, these observations are likely to aid in the development of targeted mutation detection strategies relevant for patient management. Finally, we examine the age- and sex-dependent reduced penetrance of BMPR2 mutations by reviewing bmpr2 animal models and the requirement for additional genetic and/or environmental modifiers of disease. In conclusion, these data provide compelling genetic evidence that haploinsufficiency is the predominant molecular mechanism underlying disease predisposition, and support the concept of a critical threshold of signaling activity below which disease may be precipitated.
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Affiliation(s)
- Rajiv D Machado
- Division of Medical Genetics, Department of Genetics, University of Leicester, Leicester, United Kingdom
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Wong WKP, Morse JH, Knowles JA. Evolutionary conservation and mutational spectrum of BMPR2 gene. Gene 2006; 368:84-93. [PMID: 16361068 DOI: 10.1016/j.gene.2005.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 09/27/2005] [Accepted: 10/14/2005] [Indexed: 10/25/2022]
Abstract
A variety of mutations in the bone morphogenetic protein receptor type 2 (BMPR2) have been identified in patients with pulmonary arterial hypertension. In this study, using our BMPR2 mutation database and BMPR-II protein sequences from eight distantly related species, we defined the relationship among evolutionary conservation, mutation frequency and mutation distribution. As a whole, BMPR2 is evolving slower than the average for mammalian protein-encoding genes. As expected, the kinase domain is evolving more slowly than the extracellular ligand-binding and C-terminal domains. A detailed map of evolutionary conservation shows that there are repeating peaks and valleys within the C-terminal domain, representing higher and lower evolutionary conservation. We observed a strong correlation between evolutionary conservation and the distribution of mutations along the gene. All except two, of the nineteen missense mutations occur in absolutely conserved amino acids among the vertebrate homologs. In addition, we identified six mutational hotspots (P<0.05) by comparing the observed distribution of mutations to the pattern expected from a random multinomial distribution. Furthermore, analysis of the sequence environment surrounding the mutations revealed a specific pattern of mutagenesis. Over 22% of all single base-paired substitutions and 30% of all deletions and insertions are situated within tandem or non-tandem direct repeats of at least 5-bp and may be explained by slipped-mispairing model of mutagenesis. Also, over 59% of single base-paired substitutions versus 20% of deletions and insertions are located in perfect palindromic sequences that could produce "hairpin-loop" secondary structures with relatively high thermodynamic stability under physiological conditions. In addition, 3.7% of single base-paired substitutions versus 30% of deletions and insertions are located either within or in close proximity to the Krawczak and Cooper consensus sequence (TG A/G A/G G/T A/C). Further study of the mechanism of mutagenesis in BMPR2 may help identify other potentially mutable sites and differentiate between deleterious mutations and harmless polymorphic variants.
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Affiliation(s)
- Wai K P Wong
- Department of Medicine, Columbia University/New York State Psychiatric Institute, 1051 Riverside Drive, Unit 28, Room 5917, New York, NY 10032, USA.
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Harrison RE, Berger R, Haworth SG, Tulloh R, Mache CJ, Morrell NW, Aldred MA, Trembath RC. Transforming Growth Factor-β Receptor Mutations and Pulmonary Arterial Hypertension in Childhood. Circulation 2005; 111:435-41. [PMID: 15687131 DOI: 10.1161/01.cir.0000153798.78540.87] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Pulmonary arterial hypertension (PAH) is a potentially fatal vasculopathy that can develop at any age. Adult-onset disease has previously been associated with mutations in
BMPR2
and
ALK-1
. Presentation in early life may be associated with congenital heart disease but frequently is idiopathic.
Methods and Results—
We performed mutation analysis in genes encoding receptor members of the transforming growth factor-β cell-signaling pathway in 18 children (age at presentation <6 years) with PAH. Sixteen children were initially diagnosed with idiopathic PAH and 2 with PAH in association with congenital heart defects. Germ-line mutations were observed in 4 patients (22%) (age at disease onset, 1 month to 6 years), all of whom presented with idiopathic PAH. The
BMPR2
mutations (n=2, 11%) included a partial gene deletion and a nonsense mutation, both arising de novo in the proband. Importantly, a missense mutation of
ALK-1
and a branch-site mutation of
endoglin
were also detected. Presenting clinical features or progression of pulmonary hypertension did not distinguish between patients with mutations in the different genes or between those without mutations.
Conclusions—
The cause of PAH presenting in childhood is heterogeneous in nature, with genetic defects of transforming growth factor-β receptors playing a critical role.
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MESH Headings
- Activin Receptors, Type I/genetics
- Activin Receptors, Type I/physiology
- Activin Receptors, Type II
- Amino Acid Motifs/genetics
- Amino Acid Substitution
- Antigens, CD
- Bone Morphogenetic Protein Receptors, Type II
- Child
- Child, Preschool
- Codon, Nonsense
- DNA Mutational Analysis
- Endoglin
- Exons/genetics
- Female
- Genetic Predisposition to Disease
- Genotype
- Germ-Line Mutation
- Heart Defects, Congenital/genetics
- Humans
- Hypertension, Pulmonary/etiology
- Hypertension, Pulmonary/genetics
- Infant
- Infant, Newborn
- Male
- Mutation, Missense
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/physiology
- RNA Splicing
- Receptors, Cell Surface
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/physiology
- Sequence Deletion
- Signal Transduction/physiology
- Telangiectasia, Hereditary Hemorrhagic/complications
- Telangiectasia, Hereditary Hemorrhagic/genetics
- Transforming Growth Factor beta/physiology
- Vascular Cell Adhesion Molecule-1/genetics
- Vascular Cell Adhesion Molecule-1/physiology
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Affiliation(s)
- Rachel E Harrison
- Division of Medical Genetics, University of Leicester, Leicester, UK
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